Communications spooler for a mobile robot

Abstract

A cable handling system mounted to a mobile robot to dispense and retrieve cable at zero tension includes a cable reel drive and a downstream tension roller drive that includes an idler. As a cable passes through the tension roller drive, position along the length of the cable and/or the cable speed is monitored accurately by a sensor attached to the idler. A system controller in communication with the sensor controls the cable reel drive and the tension roller drive for dispensing and retrieving cable downstream of the tension roller drive.

What is claimed is: 
     
       1. A method of controlling a length of cable between a cable reel and a tension roller drive in a cable handling system for a mobile robotic platform, the method comprising:
 rotating a tension pulley of the tension roller drive to move a dispensed or retracted length of cable; 
 estimating a stowed length of cable remaining on the cable reel; 
 computing a length of cable located between the cable reel and the tension roller drive, based at least in part on the dispensed or retracted length of cable and the stowed length of cable; and 
 rotating the cable reel to adjust the length of cable located between the cable reel and the tension roller drive. 
 
     
     
       2. The method of  claim 1 , further comprising:
 providing an idler roller in contact with the cable such that a movement of the cable causes a corresponding rotation of the idler roller; and 
 measuring the dispensed or retracted length of cable based at least in part on the corresponding rotation of the idler roller. 
 
     
     
       3. The method of  claim 1 , wherein the estimating step comprises:
 monitoring a rotation of the cable reel; 
 monitoring a rotation of the tension pulley; and 
 comparing the rotation of the cable reel and the rotation of the tension pulley. 
 
     
     
       4. The method of  claim 3 , further comprising maintaining tension on the length of cable located between the cable reel and the tension roller drive. 
     
     
       5. The method of  claim 3 , wherein the comparing step is based on the ratio of the rotation of the cable reel and the rotation of the tension pulley. 
     
     
       6. The method of  claim 3 , further comprising scaling the result of the comparing step by a coefficient. 
     
     
       7. The method of  claim 6 , wherein the coefficient comprises at least one of a cable reel internal diameter, a cable reel hub width, a cable diameter, and a cable packing fraction. 
     
     
       8. The method of  claim 4 , wherein the computing step comprises:
 estimating the length of cable located between the cable reel and the tension roller drive; and 
 comparing the estimated length of cable with a distance between the cable roller and a predetermined location on the cable reel, wherein the predetermined location is based at least in part on the stowed length of cable. 
 
     
     
       9. The method of  claim 1 , further comprising:
 measuring the dispensed or retracted length of cable based at least in part on the rotation of the tension pulley.